Universal testing machine



Feb. 11, 1936; R LEw s 2,030,457

UNIVERSAL TESTING MACHINE Filed 0ct. 12, 1932 (Sheets-Sheet 1 INVENTORFobertfi Lends,

Feb. 11, 1936. R. B. LEWIS UNIVERSAL TESTING MACHINE 4 Sheets-Sheet 2Filed OCt. 12, 1932 Pater FE ZZW'S,

Feb. 11, 1936. R. B. LEWIS UNIVERSAL TESTING MACHINE Filed Oct. 12',1932 4 Sheets-Sheet 3 I III II llll 4 IIIN I|||l IIIIIIInIII INVENTOR6'0 fiberffi leans Patented Felt. 11, 1936 UNITED STATES PATENT. urn-Iceumvsassnrasrmdssscnma RobertELe'is, mums-a to Testing 'l'inius OlsenMachine company. Phil ennsrlvsnia delphia, Pa, a corporation of P vApplication October 1:, 1m, Serial No. mass 5 Claims. (of. ass-1s)pendulum weight, that is substitute one weight for mother according tovariations in capacity. Thus when the machine is operated with alightened pendulum a number of disturbing factors are introduced, amongwhich may bementioned the increased effect of the friction due to thelessened capacity of the pendulum to overcome outside disturbances whenso lightened. Also the weight of the pendulum forms a very definite linkwith its associated parts to produce accurate indication and a change ofthat weight while maintaining the associated parts unchanged at I onceintroduces errors in the indication.

Home of the objects of the present invention are to provide an improvedtesting machine; to provideatestingmachinewherein bothlowandhighcapacity tests can be made with equal accuracy i upon the same machine;to provide a testing machine wherein the sensitivity of the indicatingscale remains constant regardless of the appliedforoe: to provide atesting mechanism wherein variation of parts one with respect toanother. such for example, as change of pendulum weight becomesunnecessary when changing the capacity of the machine; to provide amechanism wherein the maximum range of a testing machine scale can bealtered without affecting the accuracy thereof or disturbing adjuncts ofthe weighing mechanism; to provide means for varying the lever system ofa testing machine without impairing the eifeetiveness of the indicatingscale: to provide-an improved control valve for maintaining a uniformrate of travel of the load apn rins means: to provide means for ensuringa constant load in a testing machine; to provide a device for indicatingthe rate of loading of a testing machine and whereby a definite constantloading rate can be maintained; and to provide other improvements aswill hereinafter appear.

In the accompanying drawings Fig. i represents a front elevation of atesting machine embodying one form of the present invention; 8. 2represents an enlarged detail of the lever system showninthemachineofl'lg.iassettofunctionas a lever of thethird class; Fig. 8represents the same iever system as set to function as a lever of thesecond class-Fig. 4 represents a detail in side elevation of one form offulcrum pin; Pig.

5 represents asection on line H of l'ig. 4:1'lg. 6 represents a detailin side elevation of riable fulcrum lever; Fig. 7 represents a sideelevation of that portion of the machine which inconstant loadingdevice; Fig. 8 represents a detail of one form of mechanism forobtalninga predetermined rate of loading of the machine;

and Pig. 9 represents a longitudinal section of an improved valveforcausing the load applying 1 mechanism to travel at a constantrateregardless of load variation.

Referringtothedrawingsandmoreparticularly to Fig. 1. one form of thepresent invention is shown as applied to a pendulum typeof 15 universaltesting machine consisting generally of a base-unit ll mounting the loadapplying mechanism. a'weighing unit ll mounted thereon, and includingas-a part thereof the load indicator II.

in thepresentinstancetheweighing unit it is go assembled in conjunctionwith a load applying mechanismofthehydraulietypewhereinthe pressurefluidissuppliedtothecylinder is from conduit M in order to cause thelead applying crossheadlltomoveandtransmitthepullgs through thetestpieceto theyoke II. The present invention is not limited.-however, for usewith any particular kind of load pplying mechanism.

l'brtrannnitting-theloadtotheweig'hingpendulumttaleverarmllisproddedwhichisfubso crumedinanovelmannerlatertohedescribed,carryingalaterallyproiectingpinllsntingintheslottedendilofatubulsa-rodfl. 'l'helowerendofthisrodflisconnectedhyapivotiltoafulcrumarmllwhichisfulcrumedatllandss undercontrolofadash-potll.'l'hepivotllalso connectsthearmlltotwolinksllwhicharespaeedbytheroditandrisealongsidethereof for connection throughapivot 28with athrow armllkeyedoroth'erwisemadefasttoarockso shaftll.Suitabiebearingsflarecarriedbythe,casingIltolourns-ltheshaftliandthelatter mounts the pendulum 84 by whichthe applied forceismeasured. Athreadedrodll projectsfromahubflattachedtotheshaftii andass counterweightIlisthresded'upontherodfl for operation. Inordertoindicatethethrowof thependulum fltheindicstingdial If ism v dedhavingaciremaiscale sograduatedin terms of applied force. 5

Apointerliisrotatablymolmtedtoturn'witha spindle If sttheeenterofthediall2 sndthe spindle l2 is'arranged to be 'driven by a pinionmeshingwithareclprocableracibarfl. This rackbarissuitablysupportedandguidedatgg the rearof the dial it and projectsatone end totheexteriorofthecasingll whereitterminates in a knurled IIfor manual setting. The opposite end of thebar 44 terminatesin a rollerll located in the path of movement of an cording chart, the cylinder Itbeing rotated by a cable 5! arranged to follow the movement ofthecrosshead It. Thisisanywellknownformofstressstrainrecordingapparatus, suchfor example as shown in UnitedStates letters Patent No. 1,855,613.

Formountingtheleverarmllsothatitfunctionsasaleverofthethirdclasaasshownin Pig. 2, for use whenusing the machine for relativelyhlshcapacitytesmatransverseholeltisprovided throllsh thearm ",atthe oppositeside of yoke It from. thependulum It, for the receptionofaknifeedgepinil. Thispin II isremovablymountedin a bifurcated extension 52 of the casing II and its knife edgecoacts with a wearinsertltinthearmlt. Bincetheapplied force actsthroughthe yoke II to the fixed knife edge 54 projecting from both sides of thearm ll,itwillbeseen thatthepin ll becomesthe fulcrum of a third classlever which reacts through the pin It to cause a definitely proportionedmovement of the pendulum. The swing of the pendulum in turn istransmitted through the rack 44 and pinion II to turn the pointerclockwise and produce an accurate indication of the applied load. Thuswith the lever ll fulcrumedasaleverofthethirdclassandfunctioning forloads of say one thousand pounds, the.

ratio of the lever acting upon the pendulum 84 will result in a pointermovement on the scale dial I! from zero to one thousand pounds for tworevolutions of the pointer 4|. pound graduations of the scale arerelatively widelyspacedsothateachpositlonofthepointer is unmistakablyindicated.

For mounting the lever ll so that it becomes a lever of the secondclass, as shown in Fig. 3, to give a ratio adapted for low capacities,such as from zero to one hundred pounds, a transverse holeilisprovidedthroushtheendof theleverllontheoppositesideofthepinllfromthe yoke It.Awearinsertllislocatedonthelower portion of the hole ll to support theknifeedge of the pin ii. The frame It is provided with suitable ribs 51to receive the end of the lever ll between them, andholes I8 arerespectively formed in theribs I! to register withthe hole lloftheaforesaidlever. Thusthepinllcanbeinsertedthroughtheholesilandlisothatit becomes a fixed fulcrum aboutwhich the lever It canswing undertheinfiuence ofthe load applied on theyoke It. The lever ll now becomes a lever of the second class ready tofunction for low capacity loads and the ratio of the lever acting uponthe pendulum II will result in a pointer movementonthedialllfrommerotoonehundred pounds. Preferablyafullswingofthependulum It onthis ratio will cause two revolutions of thepointertogiveamaximumreadingofone hundred pounds and hence the desiredlegible readings of the graduations are obtained.

For thepurpose of obtaining anydesired rate of loading upon fliemachine, the'rear face of spoons? the dial l2 carries a circular trackill upon which an endless chain Si or like belt is arranged to travel.The track is interrupted at one point .2 to permit the chain 8| to passaround a driven sprocket or wheel I rotatably mounted within thecircumference of the track 60. Idlers 6! guide the chain ll through theopening at the point 62 and maintain the necessary tension thereon.Motion is transmitted to the driven sprocket 63 by a spindle ll carryinga disc 65 which is friction- 1 ally driven by a wheel 68 carried byalongitudinally shiftable shaft 81 having a gear 68 keyed thereon toallow free relative sliding of the shaft "2 A bearing II supports theshaft 81 and holds thegear it against movement with the shaft 1 when thelatter is shifted lengthwise. A second bearing II is provided in thecasing 33 where the shaft 81 projects conveniently for manual setting.Preferably the protruding shaft end is graduated in terms of track speedcorresponding 2 to the rate of loading upon the machine and hence theshaft can be readily positioned to give a, predetermined loading rate.The gear 88 is actuated through a suitable gear reduction I2 from aconstant speed motor 13 which is suitably mount- 2 ed within the casing33. A band 14 of spring um terlal is tensioned about the chain 8| toride therewith as a complete unitary circumference driven by the chainll to travel adjacent to the periphery of the dial II, but preferablycon- 3 cealed behind said dial. A finger I! is fixed to said band I4 andis curved outwardly therefrom to straddle the margin of the dial "andthus become visible from the front of the machine so that its rate oftravel can be used for bringing a the movement of the dial to the samespeed. In other words the finger [5 acts as a pacer for setting the loadapplying mechanism so that it applies the load at'a known rate.

For applying the load to the test piece it is 44 preferable to employ ahydraulic mechanism, the details of which are well known in the art andconsisting generalLv of a cross-head l5 moved by a plunger 11 operatingin a cylinder l3 under the action of a pressure fluid supplied by a pipe44 ll. This is the standard hydraulic operated pressure applyinscylinder employing a coil spring means 8 for returning the plunger 11 toits initial or zero position. in the present instance this supply pipeII is controlled by a rate 5( fiow valve ll operating in conjunctionwith a rate fiow indicating dial 82, and also by a supplemental valve Inconnection with this hydraulic mechanism the present inventioncomprehends a new and novel constant flow control 55 valve by means ofwhich it is possible to obtain a rate ofcross-head movement which forall practical purposes is substantially constant throughout the loadingrange of the machine. In the present instance the body 84 of this valveis provided with two axially disposed bores II and I! opening atopposite ends of the body and intercommunicating by a bore 81 of'reduced dimeter and a chamber 88 of increased diameter. The bore II ispreferably larger than the bore 82 in order to give a desireddifl'erential action and is arranged to receive a piston 88 which issupported on a stem 80 of a valve part 9|. This valve part II isarranged to control the passage 92 formed in a fitting 93 which isscrewed into the valve body at one end and at its other end is connectedto and communicates with a pipe ll leading from the discharge pipe 95 ofa pump OI. The pump it as here shown is of the rotary type driven by amotor 81. The fitting II pro-- 75 aosoasv videsaseatforthevalvepartllandwhenthe valveisopenpressurefluid iromthepump enterstheborellandcanescape therefromback tothe pump reservoir by way of the chamber 86and by-pass outlet 08. The bore as communiincreases in the cylinder itthrough the increase in load, the pressure of the load fluid upon thevalve part II at one end and upon the piston 88 at the other end resultsin a diflerential action which assists andensures the spring I inmaintaining the correct diflerential for uniform rate oi flow into thecylinder whereby a substantially constant cross-head motion is obtained.

In connection with the indicator II it should be noted that while thepointer II is actuatedby the weighing mechanism under both low and highcapacity tests, the indicating dial is provided with two sets of scalesor graduations Ill and Ill, the former being arranged to be read whenthe pointer ll isresponding to low capacity loads and the latter to beread when the pointer II is responding tohigh capacity loads. It is tobe understood that this manner of calibrating the dial with two sets ofscales is merely one way of obtaining the results, as probably inpractice each dialwillbeatwoi'aceddialhavingalowcapacity scale on oneside and a high capacity scale on the other side, whereby the dial canbe reversed when a change from low capacity testing to high capacitytesting and vice-versa is desired. Where a dial of the aforesaid twofaced type is used, a reversal is accomplished by removing the pointerll so that the dial clamping means can be released and then lifting thedial forwardly from the spindle ll, turning it over, to expose theopposite face and then replacing it in this reversed position. In theoperation of the machine of the present invention it will be assumedflrstthatthetestplecesaretobesubiectedto low capacity loads andtherefore the lever system by which the weighing mechanism is oper-'atedisarrangedasaleverofthesecondclassby the lever mtem is convertedinto one of the third classbyremoving thepin Ii andinsertingitin thehole It at the opposite end of the lever llwhereitissupportedbytheframeandbecmnesanewiulcrumsochangingtheleversystemasto bring the weighing mechanisminto operation with the indicator, so that the latter shows in wellspaced graduations the high capacity applied loads. In connection withthe lever it it should be noted that a counter-balance weight III isattachedattheproperlocationonthelever-ll'tobrmgaboutatrue'balanceoftheleverabout the pin II. This eliminates anyerror which might appear due to the unbalanced weight of the lever ll.Aho th'ebalanced condition of the lever ll aboutthepivotpinllestablishesa constant zero setting of the indicator and'thereforeanychangefromoneleversystemtotheother requires noresetting of theindicator to zero. Itwillthusbeevidentthatthefulcrumpointcan beimmediately changed from one place to anbalance of theparts.

Foraccm'atetestingitisdesirablethatthe cross-head ll apply its load tothe test piece not only uniformly but at a known rate of applicationandthatthismaybeaccomplishedthecontrol valve N with its difl'erentialaction comes into play since by setting either of the hand controlvalves 8! orlltherateof flow ofthe pressurefluid to the hydrauliccylinder can be accurately regulated. That this rate of flow will remainpractically constant is evident from the fact that both ends of thediflerential member ll are subjectedtothepreasureoi'thepumpdischargeandthrough the diflerence in thediameters of the piston II and valve I. this pressure functions tomaintain substantially the predetermined differential relation, which isinitially obtained by the setting of the spring III. In the operation ofthe valve 84 the spring III is initially set for no load condi tions inthe flow of fluid from the pump It. To regulate the loading pressure andestablish a predetermined rate of loading. the control valve 03 isclosed and the regulating valve 8| opened until the desired rate isestablished. with this rate flxed and the cross head ll moving under theappliedloadanyincreaseinbackpressureistransmitted by the pipe I! to thePiston I! so that the pressure of the spring m a proportionately m- 4creased and'a definite diflerence of pressure is maintained between thebore 02 and the chamber l. The diflerential piston construction becomesan automatic compensating means for the increase in fluid friction underload application andhencetherateofioadingresultisi'reefrom errorintroduced by fluid friction. The desired rate of loading is obtained bystarting the motor ll andadiustingthevariablespeeddisc llsothat therider or pacer ll travels about thecircumferenceofthedialattherateselectedi'orapplying the load. with thispacer ll travelling at the desiredrataoneortheotheroithevalvesll or Ncanthenbebroughtintooperationtosocontrolthepumpdisehargethatthemovementofthe cross-head will be reflected in the pointer Ii and the lattertherefore made to become coincident in its motion with the pacer ll.

Itwillnowbeapparentthatacompletetmitarytestingmaehinehaabeendcvisedwhichmregulator and application Ser. No. 690,994 for Improvement in speedcomparing device.

While only a single form is shown in which this invention may beembodied. it is to be understood that the invention is not limited toany specific construction, but might be applied to various forms withoutdeparting from. the spirit of the invention or the scope of the appendedclaims.

' Having thus described my invention, 1 claim:-

I. In a testing machine, the combination of a weighing system includinga load responsive lever, an indicator responsive to a selected loadcondition applied to said system and responsive as a function of anotherload condition, means including a removable fulcrum pin for varying thefulcrum of said lever to conform to one or another of said loadconditions, means for operating said indicator, means forming a point ofconnection between said lever and said indicator means, and means tomaintain said lever balanced about said point of connection whereby thesame zero setting of said indicator is maintained for both conditions.

2. In a testing machine, the combination of a weighing system includinga load responsive lever, an indicator, means for operating saidindicator, means forming a point of connection bctween said lever andindicator operating means, means for applying a testing load to saidlever, means providing two fulcrum saddles for said lever, a singleremovable knife, edge for selecting one or the other of said fulcrumsaddles wherebythe. operating effect of said lever can be varied at willfor different capacities, and means to maintain said lever balancedabout said point of. connection whereby the same zero setting of saidindicator is maintained for all capacities.

3. In a testing machine, an indicator, means including a weighingpendulum for operating said indicator,.a load responsive lever arrangedto opsetting of said indicator is maintained for all lever systems.

4. In a testing machine, an indicator, means including a weighingpendulum for operating said indicator, a load responsive lever arrangedto opcrate said pendulum and having two holes therein, means forming apoint of connection between saidlever and said indicating means, meansfor applying a load to said lever between said holes, a

fixed frame, a fulcrum pin for entering one or the other of said holesand engaging said frame whereby said lever system can be changed atwill, and means to maintain said lever balanced about said point ofconnection whereby the same zero setting of said indicator is maintainedfor all lever systems.

5. In a testing machine, an indicator, means including a weighingpendulum for operating said indicator, a frame having two fulcrumlocating holes therein, a lever having holes therein to reg isterrespectively with said fulcrum holes, means forming a point ofconnectionbetween said lever and said indicator means, means forapplying a load to said lever between said lever holes, a pin providedwith. a knife edge for entering either pair of registered holes wherebythe system of said lever can be changed at will, and means to maintainsaid lever balanced about said point of connection whereby the same zerosetting of said indicator is maintained for all lever systems.

ROBERT B. LEWIS.

